Improvement in elliptic springs



N. LTILGHMAN.

ELLIPTIC-SPRING.

Patented June 5,1877.v

ATTORNEYS.

N. PETERS, PHOTO-LIYNOGHAFHER. WASHINGTON. D C.

H UNITED STATES PATENT QFFICE NOAH J. TILGHMAN, OF TYASKIN, MARYLAND.

IMPROVEMENT IN ELLIPTIC SPRINGS.

Specification forming part of Letters Patent No. [91,731, dated June 5,1877 application filed May 14, 1877.

To all whom it may concern:

Be it known that I, NOAH J. TILG-HMAN, of Tyaskin, in the county ofWicomico and State of Maryland, have invented a new and ImprovedElliptic Spring; and I do hereby declare that the following is a full,clear, and exact description of the same, reference being had to theaccompanying drawing, forming part of this specification, in which thefigure is a side view'of the spring, with the axle and spring-bar indotted lines.

My invention relates to an improvement in elliptic springs designed moreparticularly for the use of vehicles, but applicable for other purposes.

The invention belongs to that class of springs in which the plates aremade of a single coninnons piece of metal bent around in elliptical formwithout end joints, and placed one within the other.

The improvement consists in bringing the ends of the plates together sothat the free ends of each plate abut, and in riveting said free ends toa lap-joint plate, which performs the double function ofconnectin g theends of the plate and of separating and removing an y one springof theseries from the next adjacent ones, so that such springs do not toucheach other at this point, and whereby each spring is rendered capable offree, easy, and independent movement, without impinging against the others, which, to a great extent, obviates the dis agreeable creakingnoise.

In the drawing, A A A represent three concentrically-arranged ellipticalsprings, made each of a single plate of steel bent around withoutjoints, and with their free ends abutting against each other in themiddle parts of the spring or minor axis of the ellipse. These springsare fastened to each other and to the axle of the vehicle below by meansof bolts a a, whichpass through centrally-arranged holes in saidsprings, and are fastened to each other at the top, and to thespring-bar of the vehiole-body by means of bolts b b.

In order to connect the free ends of the plate of each spring, so as tomake each spring integral in itself, I bring the said ends together soas to abut, and apply plates 0 c c to the ends of each spring, the saidplates being riveted to the said ends. These plates,

which constitute the only novel feature of my invention, serve a twofoldpurpose in this connection. In the first place, they serve to connectand secure the ends of each spring, to make each spring integrallyseparable from the rest. In addition to this function, also, when thesprings are arranged in series, they alternate with the springs, andthus serve to separate and remove the surface of any one spring from thesurface of the next adjacent springs, whereby each spring is permittedto have its own free and independent movement without impinging,griping, and binding against the others, and whereby is avoided therubbing of the paint, the rusting of the metal, and the consequentdisagreeable creaking noise attending the same.

The merit of the continuous form of elliptical spring bent aroundwithout end joints is that a much stronger and stifi'er spring issecured in proportion to the amount of metal used, for the tension ofthis spring is represented not only by the elasticity of the long curve,(as is the case when the springs are jointed at their ends,) but thiselasticity is reenforced by the elasticity of the short bend at eachend, which makes a single-plate spring of this form possess the abilityto carry the same burden that a three-plate leaf-spring does whenjointed at the end, the thickness of plate being the same in each.

This property, it will be seen, enables me to construct vehicles with asufficient tension to the spring, but lighter than other vehicles by theamount of weight dispensed with in the spring, While at the same time,by dispensing with the joints and leaves, the manufacture of the springis greatly simplified, and their production cheapened.

Another important advantage is that, with this construction andarrangement, one section of the spring may be removed from the center,or an additional one may be added thereto, either to diminish orincrease the force in adapting the spring to greater or less burdens,the symmetrical arrangement of the one spring within the other readilypermitting this without injury to the others, and without otheralteration or adaptation than the simple loosening of the bolts, and theinsertion or removal of the plate.

as described, and having their free ends united in the center, andseparated by lap-joint plates 0 c 0, substantially as described, and forthe purpose set forth.

NOAH J. TILGHMAN.

Witnesses:

SOLON O. KEMON, CHAS. A. PET'IIT.

